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