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