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