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