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