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