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