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