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