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