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