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