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