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