It reminds me of my bedroom as a teenager... everything stayed where I dropped it or dragged it until I picked it up and moved it again. And I have never managed to figure out how to programmatically move those items either.
Looks like the Lebans article from Majp at least takes a whack at it. Give that a read.
If you have SQL server available, you could upsize the database and use the diagramming tool there. You can have multiple diagrams per database so sometimes it makes sense to organize a large schema by function. The diagram window shows you page breaks and you can change the size of the diagrams. For gross layout, you can work with the diagram at 25% so you can move tables around very easily. Then to refine the layout, go as close to full size as you need.
The only way I have found besides moving them yourself is clearing the windows, do not break the relationships, and then click All Relationships. Note, it just makes them all line up, there is no real order to them but at least they are not overlapping each other.