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