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