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