Hi @anton e thanks for posting in the community. That's a great question! If you have access to the feature you can compare diagram versions using Revision History. 

If you open revision history you can select different versions and compare them by clicking the blue 'Compare Version' button found at the bottom right of the revision history view. 

For more information I recommend taking a look at the Compare Versions section of our Revision History article from the Help Center. 

I hope this helps. Feel free to let me know if you have any additional questions!