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)(11,15)(12,16)(13,17)(14,18)(19,23)(20,22)(21,24)(25,26,30,28)(27,31,34,36)(29,37,39,32)(33,35,40,38)(2,5)(6,8)(9,11,14,20)(10,15,18,22)(12,21,13,19)(16,24,17,23)(25,27)(26,31)(28,36)(29,38)(30,34)(32,40)(33,37)(35,39)(10,16)(11,19)(12,13)(17,18)(20,21)(23,24)(25,28,30,26)(27,33,34,40)(29,32,39,37)(31,38,36,35)(1,3,4,7)(2,6,5,8)(11,20)(15,22)(19,21)(23,24)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.