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