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