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