[gregoire]

Not exactly what you might be looking for, but check out https://monodraw.helftone.com/ and http://asciiflow.com/

[masklinn]

Asciiflow is what I've been using so far, but you have to hand-roll graphs.

The screenshot on monodraw's home look good, might be what I've been looking for.

[hokumguru]

I've used monodraw and I can say it's great