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