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