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