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