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