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