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