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