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