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