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