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