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