Order Configurator : AutoMatStore.com In the drop down on the upper left, choose 2013 model year, then Tesla, then S. It then gives you the mat choices for the entire car. Colors can be seen on the lower segment of that page. I think the ebony is the best choice if you want a dark color compatible with the stock dark gray/black carpet liners. The blue might also be a good choice for those with blue cars. I almost chose that color myself.
The color I ordered is called Parchment (number 066). I paid $597.00 for the entire set, including shipping. See this thread for some of the colors pictured near the tan seats and stock carpet liner: Will after market mats be necessary or will the Tesla mats be up to snuff? - Page 2