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