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