We have all been there - trying to put together a PowerPoint Presentation / Visio Architecture around cloud computing - and coming face to face with the fact that we are engineers, not artists. Fortunately, there is help at hand! Visio Stencils / PNGs for all things Microsoft Cloud (Azure and Enterprise) can be downloaded here:
http://www.microsoft.com/en-us/download/details.aspx?id=41937
Cheers,
Ben