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