ProB can generate a wide range of visualizations for your models. For this ProB generates first a textual representation of a graph in the "dot" format. This information is typically saved to a file which has the same name and path as your main model, but has a ".dot" extension. It then uses GraphViz to render this file. For this it can either make use of the "dot" program to generate a Postscript file (generating a file with the ".ps" extension), or it uses a Dot-Viewer (such as "dotty") to view the file directly.
Then set or check the following preferences:
Note: you can use the "Pick" button to locate the dot program and the dot viewer.
In case you want to use the Postscript option, also make sure that you have a viewer for Postscript files installed, and set the following preference:
.