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