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