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