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