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