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