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