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