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