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