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