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