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