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