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