I have gotten good results drawing FSMs using the VauCanSon-G package.
It's pretty easy to use for simple FSMs and has some advanced feature as
well.
http://www-igm.univ-mlv.fr/~lombardy/Vaucanson-G/
Tom VanDrunen
Thomas VanDrunen
Department of Mathematics and Computer Science
Wheaton College
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Dia ton oiktirmon tou Theou, ten logiken latreian humon.
(In light of the mercies of God, your rational service.) Rom 12:1