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