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