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