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