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