This is where Google can be your friend: look for "shell programming flow diagram" or "shell programming flowchart."
One that I have seen (free to try, $99 to buy) is Code Visual to Flowchart (
http://download.cnet.com/Code-Visual...-10072756.html). Seems to work fairly well. Downside, it's Windows.
There's also Aivosto (
http://www.aivosto.com/) that looks interesting.
There are quite a few listed, take a look and see what interests you.
Hope this helps some.