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