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