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