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