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