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