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