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