I have bought a HC-05 Bluetooth Module, which I connect to Arduino MEGA 2560. How do I read the data that Arduino send over the Bluetooth in the laptop and do some graphic representation of the values that Arduino sends me.
Pair with the Bluetooth module with your laptop.
Open the serial port provided by the Bluetooth connection using your favourite PC programming language.
Display the data you read in whatever format you want.
A cheap and dirty way is to set Tools->Port to select the bluetooth connection and use Tools->Serial Plotter to graph the numbers it receives.