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