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