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