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