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