One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(5,8)(9,10,16,19,15,12,14,20)(11,21,31,25,24,33,23,17)(13,27,28,26,30,34,29,18)(22,32,36,40,38,39,37,35)(1,2,4,6)(3,8,7,5)(9,11,16,31,15,24,14,23)(10,17,20,33,12,25,19,21)(13,22,29,37,30,38,28,36)(18,32,27,40,26,39,34,35)(1,3,4,7)(2,5,6,8)(9,12,15,10)(11,17,24,25)(13,26,30,18)(14,20,16,19)(21,31,33,23)(22,32,38,39)(27,29,34,28)(35,37,40,36)(9,13,14,28,15,30,16,29)(10,18,19,34,12,26,20,27)(11,22,23,36,24,38,31,37)(17,32,21,35,25,39,33,40)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.