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