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