I think that the graph in jbpm-console is not being auto-generated. You have to upload a .png image of it. I didn't check the code, so I'm not sure about it. Using Drools/jBPM5 APIs, you can get the process structure and the runtime information. If you want to create a graphical representation of your process, then (I think) you are on your own. Maybe you can take a look at jBPM eclipse plugin or even Oryx to get an idea of how to do that. jBPM Eclipse plugin creates the image from the process object model. In the other hand, Oryx does it from the xml definition of your process.
Best Regards,