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