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