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