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