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