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