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