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