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