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