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