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