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