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