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