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