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