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