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