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)(11,14)(12,17)(13,16)(15,20)(18,22)(19,24)(21,23)(25,26,31,32)(27,35,37,28)(29,38,36,33)(30,34,39,40)(2,6)(3,8)(9,10)(11,14)(12,15)(13,16)(17,20)(18,22)(19,23)(21,24)(25,27,31,37)(26,28,32,35)(29,30,36,39)(33,34,38,40)(1,3)(2,4)(5,8)(6,7)(10,11)(15,17)(16,18)(23,24)(26,32)(28,35)(33,38)(34,40) involution — undirected(1,3)(2,4)(5,8)(6,7)(9,11,14,10)(12,17,20,15)(13,16,22,18)(19,23,21,24)(25,28)(26,27)(29,34)(30,33)(31,35)(32,37)(36,40)(38,39)(1,4)(2,3)(5,7)(6,8)(9,12,14,20)(10,15,11,17)(13,21,22,19)(16,24,18,23)(25,29)(26,33)(27,30)(28,34)(31,36)(32,38)(35,40)(37,39)(9,13,14,22)(10,16,11,18)(12,19,20,21)(15,23,17,24)(25,30)(26,34)(27,36)(28,38)(29,37)(31,39)(32,40)(33,35)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.