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