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