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