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)(11,19)(12,18)(13,16)(14,20)(15,17)(21,22)(23,24)(25,26)(27,28)(29,33)(30,31)(32,36)(34,35)(37,40)(38,39)(1,2)(3,6)(4,7)(5,8)(9,11,15,13)(10,16,17,19)(12,21,20,23)(14,22,18,24)(25,27,30,32)(26,28,31,36)(29,37,38,34)(33,40,39,35)(10,17)(12,20)(16,19)(21,23)(26,31)(27,32)(29,38)(35,40) involution — undirected(1,3,5,4)(2,6,8,7)(9,12,15,20)(10,18,17,14)(11,21,13,23)(16,24,19,22)(25,26)(27,28)(29,33)(30,31)(32,36)(34,35)(37,40)(38,39)(1,3,5,4)(2,6,8,7)(9,13,15,11)(10,19,17,16)(12,23,20,21)(14,24,18,22)(25,28)(26,32)(27,31)(29,35)(30,36)(33,37)(34,39)(38,40)(1,4,5,3)(2,7,8,6)(9,14,15,18)(10,20,17,12)(11,22,13,24)(16,23,19,21)(25,29,30,38)(26,33,31,39)(27,34,32,37)(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.