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