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