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