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