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