This plugin for TiddlyWiki 2.x
introduces the <<graph>> macro to create and edit graphs in a WYSIWYGish manner.
It uses the Vis.js library, so various showcases can be found at https://visjs.github.io/vis-network/examples/. See also the demo page: https://yakovl.github.io/TiddlyWiki_GraphTools/.
Available to install via ExtensionsExplorerPlugin, like many others (to find it, install the central collection and YLExtensionsCollection from it).