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