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