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