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