As more and more objects move into the cloud the ability to build clear network diagrams becomes more important, today I found the Visio stencils and general use PNG for the cloud objects to build Azure (and other cloud) network diagrams.
Microsoft Azure, Cloud and Enterprise Symbol / Icon Set – Visio stencil, PowerPoint, PNG:
To use them in Visio you will want to open the Zip that you download and then copy the Visio Folder into the My Shapes Directory on your PC, they will then show up under the My Shapes Folder in Visio.
Detailed Instructions are here:
To use the images in PowerPoint you can place them anywhere on you need them and then drag and drop the images into your presentation.