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