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