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