I made covers for my Silhouette SD and shared them with friends and I made another one for my Silhouette Cameo when I got it last November. I was going to make a tutorial to share on my blog but I found one on Pinterest that the creator is generously sharing. I made mine exactly the same way. This cover is simply for protecting your machine from dust.
For the tutorial: Silhouette cover tutorial
Don't forget to check out my new cards on my previous posts.
The website for the link above has been under construction for a while now so I went searching for another tutorial with a free pattern and found this: http://kathleendriggers.com/2012/02/04/free-silhouette-cameo-dust-cover-pattern/
Update: October 28, 2014
Here is another link, it's working a/o this writing :-): http://kathleendriggers.com/free-silhouette-cameo-dust-cover-pattern/