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