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