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