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