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