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