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)(27,37,28,34,38,33,39,40)(9,11,13,19)(10,14,16,17)(12,20,21,18)(15,23,24,22)(25,27,31,38)(26,33,36,37)(28,29,39,32)(30,40,35,34)(1,3,5,4)(2,6,7,8)(25,28)(26,34)(27,29)(30,33)(31,39)(32,38)(35,37)(36,40)(1,4,5,3)(2,6,7,8)(9,12,13,21)(10,15,16,24)(11,18,19,20)(14,22,17,23)(25,29,31,32)(26,35,36,30)(27,28,38,39)(33,40,37,34)(10,16)(14,17)(15,24)(22,23)(25,30,32,36,31,35,29,26)(27,34,28,33,38,40,39,37)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.