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