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