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