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