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