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