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