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