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)(25,26)(27,35)(28,31)(29,33)(30,34)(32,38)(36,40)(37,39) involution — undirected(1,3,5,7)(2,6,4,8)(11,17)(15,21)(18,23)(22,24)(25,27)(26,32)(28,35)(29,36)(30,37)(31,38)(33,34)(39,40)(2,4)(3,7)(10,14)(15,21)(16,19)(22,24)(29,37)(30,36)(33,39)(34,40) 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)(25,28,31,26)(27,35,38,32)(29,33,37,39)(30,40,36,34)(1,3)(2,6)(4,8)(5,7)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,29,31,37)(26,33,28,39)(27,36,38,30)(32,34,35,40)(1,4,5,2)(3,8,7,6)(9,12,13,20)(10,16,14,19)(11,18,17,23)(15,22,21,24)(25,30,31,36)(26,34,28,40)(27,37,38,29)(32,33,35,39)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.