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