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