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