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