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