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