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