By plot graph, I am assuming that you are referring to the traditional plot pyramid which has five points that could lay along the lines of a pyramid shape:
2. Rising Action/Complication
4. Falling Action/Denouement
As this relates to Hamlet, a reader can roughly look at the five acts and lay the events on the graph that way. Here is what a brief overview of the play would like like:
1. Exposition: arrival of the ghost and subsequent conversation with Hamlet; establishment of Hamlet's attitude toward his mother and her hasty marriage to Claudius; introduction of Polonius and his children, Ophelia and Laertes
2. Rising Action/Complication: Hamlet's acting crazy; the arrival of Rosencrantz and Guildenstern as spies on Hamlet; arrival of the players who will ultimately enact a play which could "catch the conscience of the king"
3. Climax: The play-within-a-play reveals Claudius's guilt; Hamlet decides NOT to kill Claudius while he is act prayer; Hamlet accidentally kills Polonius, thinking he was Claudius, hiding in the Queen's rooms.
4. Falling Action: Hamlet plays games with Claudius and is ultimately sent away to England; Opehlia goes crazy; Laertes returns to Elsinore determined to kill Hamlet as vengeance for his murdered father; Claudius and Laertes plan the fencing match
5. Resoultion: Hamlet has a new understanding of life and death; he reveals that he is ready to do whatever it takes (such as sending Rosencrantz and Guildenstern to their death) to survive this situation; Hamlet resolutely heads into the fencing match; Laertes and Hamlet mortally wound each other; Gertrude dies by poison; Claudius dies by sword and poison; Fortinbras arrives to take over the throne.