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