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