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