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