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