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