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