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