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)(11,14)(12,19)(13,15)(16,21)(17,23)(18,24)(20,22)(26,31)(27,34)(33,37)(35,40)(3,7)(5,8)(9,11,13,17)(10,14,15,23)(12,20,21,18)(16,24,19,22)(25,26,30,31)(27,32,34,28)(29,37,38,33)(35,36,40,39)(1,2)(3,5)(4,6)(7,8)(10,15)(11,17)(16,19)(18,20)(27,34)(28,32)(35,40)(36,39) involution — undirected(9,10)(11,14)(12,16)(13,15)(17,23)(18,22)(19,21)(20,24)(25,27)(26,32)(28,31)(29,35)(30,34)(33,39)(36,37)(38,40) involution — undirected(1,3)(2,5)(4,7)(6,8)(9,11)(10,14)(12,18)(13,17)(15,23)(16,22)(19,24)(20,21)(25,28,30,32)(26,27,31,34)(29,36,38,39)(33,35,37,40)(1,2)(3,5)(4,6)(7,8)(9,12,13,21)(10,16,15,19)(11,18,17,20)(14,22,23,24)(25,29,30,38)(26,33,31,37)(27,35,34,40)(28,36,32,39)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.