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