[perihelions]

The graphics look identical to those in Hopcroft & Ullman's "Introduction to Automata Theory, Languages, and Computation" (like the convention that they use a double-circle to denote accepting states). I imagine they're GraphViz-based: it's very easy [0] to draw these in GraphViz. I don't know what Hopcroft & Ullman used though, because that one was published in 1979, and GraphViz didn't exist before 1991. Suddenly I'm curious what the state of the art for vector diagrams was in 1979...?

[0] e.g. https://graphviz.org/Gallery/directed/fsm.html

[therealcamino]

Maybe something related to 'pic'? This doc on it is a revised version of a 1984 edition, so maybe it's a little too late, but there are references to other systems back to 1977 or so.

https://pikchr.org/home/uv/pic.pdf