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