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