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