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