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