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