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