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