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