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