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