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