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