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