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)(2,5)(3,8)(9,10)(11,16)(12,17)(13,18)(14,15)(19,23)(20,24)(21,22)(25,26,30,29)(27,31,33,35)(28,32,36,38)(34,39,37,40)(1,3,6,8)(2,7,5,4)(11,17)(12,16)(13,21)(18,22)(26,29)(27,33)(28,36)(39,40)(1,4)(2,3)(5,8)(6,7)(9,11)(10,16)(12,15)(13,19)(14,17)(18,23)(20,22)(21,24)(25,27)(26,31)(28,37)(29,35)(30,33)(32,40)(34,36)(38,39) involution — undirected(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)(27,34)(29,38)(30,36)(31,39)(33,37)(35,40)(1,4)(2,3)(5,8)(6,7)(9,13,14,21)(10,18,15,22)(11,19,17,24)(12,20,16,23)(25,29,30,26)(27,35,33,31)(28,38,36,32)(34,40,37,39)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.