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