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