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