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