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