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