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