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