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