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