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