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