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