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