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