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