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)(11,13)(12,15)(14,16)(18,21)(19,23)(25,26,30,31)(27,28,35,32)(29,37,39,33)(34,40,38,36)(2,3)(6,7)(9,11,14,15)(10,12,16,13)(19,23)(22,24)(26,31)(28,32)(33,37)(36,40)(1,2,5,3)(4,7,8,6)(9,12,14,13)(10,15,16,11)(17,18)(19,22)(20,21)(23,24)(25,27)(26,32)(28,31)(29,38)(30,35)(33,36)(34,39)(37,40)(1,3,5,2)(4,7,8,6)(9,13,14,12)(10,15,16,11)(17,19)(18,22)(20,23)(21,24)(25,28,30,32)(26,27,31,35)(29,36,39,40)(33,34,37,38)(1,4)(2,6)(3,7)(5,8)(9,10)(11,12)(13,15)(14,16)(25,29,30,39)(26,33,31,37)(27,34,35,38)(28,36,32,40)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.