First I download the Microsoft Visio 2010 and SharePoint 2010 Extensions for System Center 2012 from here
http://www.microsoft.com/en-us/download/details.aspx?displaylang=en&id=29268

The install doc says I need these pre-requisites:

• System Center 2012 – Operations Manager console.
• As an alternative, you can also install the Authoring Console from Operations Manager 2007 R2.
• Microsoft Visio 2010 Professional or Premium edition
• Visual Studio Tools for Office 2010
• The Microsoft .NET Framework 4.0

I am running Windows 8 with Visio 2013.

After the install, I launch Visio 2013 and get this message. I click Install.

Now I create Blank Drawing.

At the top I see a new Tab called Operations Manager

I click Configure.

I give it a Name and my SCOM 2012 Web Console address.  I also select Automatic data refresh

Now I just click Insert Shape and add the SCOM object I want in my diagram.

It would be nice if I could multi-select here.

Also I add the Dashboard status so I  know if the link to SCOM is working or not.

Here is my first diagram/dashboard.  It was easier that I thought.   I see tons of possibilities using this.