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