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