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