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