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