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)(25,26,30,32,28,31,29,34)(27,33,37,39,35,38,36,40)(2,6)(3,4)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(26,31)(32,34)(33,38)(39,40) involution — undirected(1,2)(3,8)(4,7)(5,6)(26,32)(29,30)(31,34)(33,39)(36,37)(38,40) involution — undirected(1,3,5,4)(2,7,6,8)(11,18)(14,17)(19,24)(22,23)(25,27)(26,33)(28,35)(29,36)(30,37)(31,38)(32,39)(34,40)(1,4,5,3)(2,7,6,8)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(26,31)(27,35)(32,34)(36,37)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.