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