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