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