Is it possible to show graphical view of Process instance on Dashboard.?...

Yes you can given the viewer has Admin priv over the process model. Having said that, I'd be interested to know what's the use case? If you want the user to see the flow, can you not provide them with a help link that takes them to the documentation page for the model?

Yes you can given the viewer has Admin priv over the process model. Having said that, I'd be interested to know what's the use case? If you want the user to see the flow, can you not provide them with a help link that takes them to the documentation page for the model?