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