The Business Process Diagrams as you can find in the MSDN help files are consolidated in one Visio file on partnersource.
However the file you currently can download is a ZIP file. Once downloaded you need to rename the file extension to .VSDX. That will give you a Visio file with the diagrams for you to modify according to your own customizations.
Seems like you have to have visio 2013. Visio 2010 does not work.
Any chance you guys can create another version or do we have to have 2013?
Right, great feedback. Of course there is the free Visio 2013 Reader, but that does not allow you to edit according to your business modifications. Please, could you provide this feedback at the partnersource page as well. There they are in control of the way information is published. Enjoy.