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)(28,31)(29,34)(32,38)(33,36)(35,40)(37,39)(3,8)(5,7)(11,15)(14,16)(17,18,20,22)(19,21,23,24)(26,27)(31,33)(32,34)(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)(28,33,36,31)(29,32,38,34)(35,39,37,40)(1,3)(2,5)(4,8)(6,7)(9,11)(10,14)(12,15)(13,16)(17,18)(19,21)(20,22)(23,24)(25,28,30,36)(26,31,27,33)(29,37,38,35)(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)(25,29,30,38)(26,32,27,34)(28,35,36,37)(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.