[Zope] Any tool there to draw finite-state-automata-diagrams

do document the dialog states im doing w Zope? It just needs to draw circles and arcs (preferably anchored on the circles) with directions and i'd like to attach small text fields to both circles (=states) and arrows (=transitions). For db-design, i use S-Designor (free!!) and it sure is one of the finest tools i've ever seen. I want something similar just to draw diagrams. Thanks in advance.