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