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