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