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