@pout said:

Why don't you just send the data through JSON to a htmlpage and use that combined with existing chart creator?
Like this one: http://www.anychart.com/products/anychart/overview/

Should be pretty simple.

Are you in the correct topic, Pout?

AnyChart does not produce diagrams, it produces charts.
And yes it's a minimum of 500 dollars "simple".

Jim had some success using GraphViz, which actually has two examples of state diagrams:

finite state machine* LR(0) state graph