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