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