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