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