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