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