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