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