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