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