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