One vertex per element, one color per generator, with an edge from x to x·s.
(2,5)(3,6)(7,8)(9,10,16,19,22,18,29,30,15,12,14,28,13,20,33,32)(11,21,31,37,25,27,38,40,26,36,24,39,23,17,34,35)(1,2,6,8,4,7,3,5)(9,11,22,25,15,26,13,23)(10,17,20,36,12,27,18,21)(14,24,33,34,16,31,29,38)(19,35,32,39,28,40,30,37)(1,2,4,7)(3,8,6,5)(9,12,15,10)(11,21,26,36)(13,20,22,18)(14,30,16,32)(17,23,27,25)(19,29,28,33)(24,35,31,40)(34,39,38,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.