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