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