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