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