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)(15,19)(17,21)(18,22)(23,24)(26,32)(30,34)(33,35)(37,40) involution — undirected(1,2,5,6)(3,7,4,8)(9,11)(10,15)(12,16)(13,18)(14,19)(17,22)(20,23)(21,24)(25,26,31,32)(27,35,29,33)(28,34,38,30)(36,37,39,40)(1,3,5,4)(2,7,6,8)(9,11)(10,15)(12,16)(13,18)(14,19)(17,22)(20,23)(21,24)(25,27,31,29)(26,33,32,35)(28,36,38,39)(30,37,34,40)(1,3,5,4)(2,7,6,8)(9,12,14,10)(11,16,19,15)(13,20,21,17)(18,23,24,22)(25,28)(26,34)(27,36)(29,39)(30,32)(31,38)(33,40)(35,37)(9,11)(10,16)(12,15)(13,18)(14,19)(17,23)(20,22)(21,24)(25,29,31,27)(26,33,32,35)(28,36,38,39)(30,40,34,37)(1,4,5,3)(2,8,6,7)(9,13,14,21)(10,17,12,20)(11,18,19,24)(15,22,16,23)(25,30,31,34)(26,28,32,38)(27,37,29,40)(33,36,35,39)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.