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