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