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