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