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