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