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)(11,12,17,20)(13,16,23,24)(18,19,21,22)(25,26,31,34)(27,29,36,33)(28,37,30,32)(35,39,38,40)(2,5)(6,7)(10,15)(11,17)(16,24)(18,21)(25,27)(26,29)(28,38)(30,35)(31,36)(32,39)(33,34)(37,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(10,15)(11,17)(16,24)(18,21)(25,28,31,30)(26,32,34,37)(27,35,36,38)(29,40,33,39)(1,2)(3,6)(4,5)(7,8)(9,11)(10,12)(13,21)(14,17)(15,20)(16,22)(18,23)(19,24)(25,29,31,33)(26,27,34,36)(28,39,30,40)(32,38,37,35)(1,3,4,8)(2,6,5,7)(9,12)(10,11)(13,22)(14,20)(15,17)(16,21)(18,24)(19,23)(25,27)(26,33)(28,35)(29,34)(30,38)(31,36)(32,39)(37,40)(9,13,14,23)(10,16,15,24)(11,18,17,21)(12,19,20,22)(25,30,31,28)(26,32,34,37)(27,35,36,38)(29,39,33,40)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.