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