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