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