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