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