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