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