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