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