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