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