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