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