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