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