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