http://ecx.images-amazon.com/images/I/41qwArXPFIL.jpgHere it is talking about microfibre fabric rather than leather, but it seems to be a light tan colour; the 'natural' tan colour is rather orangey and not terribly fashionable, and as you already have a darker version, my vote would go to a lighter tan, as shown here. Seems to be a US term, so might be worth investigating some US sites in particular.
BTW, 'fauve' is NOT at all the same colour as 'tan' — it more normally translates 'fawn' or 'tawny'; however, being paler and less coloured than 'proper' tan, it might well be just what you need here!
Well, interestingly enough, this colour site does make it look rather tan-like:
http://pourpre.com/chroma/dico.php?typ=fiche&ent=fauveHowever, here someone describes this lighter colour as 'fauve', which is what I would have expected it to be, and which does indeed seem to me to correspond to your 'coaster tan':
http://images02.olx.fr/ui/4/77/93/71137493_2-SALON-CUIR-COUL...