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