A year ago, Microsoft released an updated set of Visio Stencils with icons for Office 365 and related products. They updated the set slightly and also provided the option to download the “older 2012 version”:
These stencils contain more than 300 icons to help you create visual representations of Microsoft Office or Microsoft Office 365 deployments including Skype for Business, Microsoft Exchange Server 2013, Microsoft Lync Server 2013, and Microsoft SharePoint Server 2013. The zip file now includes both stencil sets from 2012 and 2014.
Here’s an overview of all icons in the newest version: