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