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