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