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