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