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