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