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