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