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