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