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