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