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