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