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