If you want to create a diagram and not need automatic directed graph layout using sugiyama algorithm this can be some software options to use

railroad diagram generator from parser grammar

https://bottlecaps.de/rr/ui

uml diagram using plantuml

https://www.planttext.com/

https://plantuml-editor.kkeisuke.com/

https://umltree.com/

https://sujoyu.github.io/plantuml-previewer/

https://plantuml.com/



    Markdeep https://casual-effects.com/markdeep/
    markdown, ascii-to-all

    Svgbob https://ivanceras.github.io/svgbob-editor/
    ascii-to-all

    Archetype https://fatiherikli.github.io/archetype/
    ascii-drawing

    Textik https://textik.com/
    ascii-drawing

    ASCIIFlow http://asciiflow.com/
    ascii-drawing

    Pikchr https://pikchr.org/home/pikchrshow
    all

    Kroki https://kroki.io/
    BlockDiag, SeqDiag, ActDiag, NwDiag, PacketDiag, RackDiag, BPMN, Bytefield, PlantUML, Ditaa, Erd, Excalidraw, GraphViz, Mermaid, Nomnoml, PlantUML, SvgBob, UMLet, Vega, Vega-Lite, WaveDrom

    BPMN Sketch Miner https://www.bpmn-sketch-miner.ai/
    BPMN/flow

    Webgraphviz http://www.webgraphviz.com/
    graphviz

    Viz.js http://viz-js.com/
    graphviz

    Edotor https://edotor.net/
    graphviz

    nomnoml http://www.nomnoml.com/
    activity, class
    Source: https://github.com/skanaar/nomnoml

    CodeUML http://codeuml.com/ (dead)
    uml
    Source: https://github.com/oazabir/codeuml

    yuml https://yuml.me/diagram/scruffy/class/draw
    uml

    PlantText http://www.planttext.com/planttext
    activity, class, component, object, use case, state, graphviz, sequence, gui, earth

    PlantUML http://www.plantuml.com/plantuml/uml/
    activity, class, component, object, use-case, sequence, state, deployment, timing, gui, archimate, gantt, mindmap, tree, math, entity-relationship

    Umple Online http://cruise.site.uottawa.ca/umpleonline/
    class, state, composite

    ZenUML https://app.zenuml.com/
    sequence

    DotUML https://dotuml.com/playground.html
    class, use case, sequence, state, deployment, graphviz

    QuickDBD https://app.quickdatabasediagrams.com/#/
    entity-relationship

    dbdiagram https://dbdiagram.io/d
    entity-relationship

    WebSequenceDiagrams https://www.websequencediagrams.com/
    sequence

    SVG Sequence Diagram http://sullerandras.github.io/SVG-Sequence-Diagram/
    sequence

    JUMLY http://jumly.tmtk.net (dead)
    sequence
    Source: https://github.com/tmtk75/jumly

    js sequence diagrams http://bramp.github.io/js-sequence-diagrams/
    sequence

    swimlanes https://swimlanes.io/
    sequence

    SequenceDiagram https://sequencediagram.org/
    sequence

    GraphUp https://graphup.co/ (broken)
    sequence, gantt

    Text Diagram http://weidagang.github.io/text-diagram/
    ascii sequence
    Source: https://github.com/weidagang/text-diagram

    ASCII Sequence Diagram Creator https://textart.io/sequence
    ascii sequence

    Chart Mage http://chartmage.com/index.html
    sequence, flow

    flowchart.js http://flowchart.js.org/
    flow

    drawthe http://go.drawthe.net/
    network
    Source: https://github.com/cidrblock/drawthe.net

    mermaid https://mermaid-js.github.io/mermaid-live-editor/
    flow, sequence, class, state, entity-relationship, gantt, pie, journey

    Diagram.codes https://www.diagram.codes/
    flow, sequence, graph, tree, onion, stack, system, timeline, mindmap

    Blockdiag http://interactive.blockdiag.com/
    block, activity, network, rack/stack, packet

    state machine cat https://state-machine-cat.js.org/
    state
    Source: https://github.com/sverweij/state-machine-cat

    MetaUML https://metauml.denksoft.com (dead)

    Railroad Diagram Generator http://www.bottlecaps.de/rr/ui#_StringLiteral
    railroad/syntax

    Gleek https://www.gleek.io/
    architecture

    Ilograph https://app.ilograph.com/
    architecture

    Structurizr https://structurizr.com/dsl
    architecture

    Penrose https://github.com/penrose/penrose
    penrose

    code2flow https://app.code2flow.com/
    flow

    flowchart.fun https://flowchart.fun/
    flow

    WaveDrom https://wavedrom.com/editor.html
    timing

    CLI Text to Diagram Tools
        perl graph-easy http://bloodgate.com/perl/graph/index.html #cli
        flow
        Doc: https://developpaper.com/recommend-a-tool-for-making-ascii-flow-chart-graph-easy
        Example: graph-easy <<< [node 1]->[some text]-[this][node 1]->[branch]

javascript directed graph layout

single file C graph layout library

https://notabug.org/mooigraph/sfgraph