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