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