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