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)(27,31)(28,30)(29,32)(33,35)(34,39)(36,37)(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)(25,26,30,28)(27,31,35,33)(29,32,37,36)(34,39,38,40)(10,14)(15,17)(16,22)(23,24)(26,28)(29,37)(31,33)(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)(25,27,30,35)(26,31,28,33)(29,38,37,34)(32,40,36,39)(9,10)(11,17)(12,16)(13,14)(15,19)(18,24)(20,23)(21,22)(25,28,30,26)(27,33,35,31)(29,36,37,32)(34,40,38,39)(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)(26,32)(27,34)(28,36)(30,37)(31,39)(33,40)(35,38)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.