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