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