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