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