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