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