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