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