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