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