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