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