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