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