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