New: See ansible-role-graph-tool for an automated way to install graph-tool and dependencies on many Ubuntu/Debian distros with Ansible
Here are the steps to install graph-tool on Ubuntu 14.04, including all the prerequisites:
sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
sudo apt-get update
sudo apt-get -y upgrade
sudo apt-get -y install expat
sudo apt-get -y install libsparsehash-dev
sudo apt-get -y install gtk+3
sudo apt-get -y install libboost-all-dev
sudo apt-get -y install graphviz
sudo apt-get -y install build-essential
sudo apt-get -y install libcairo2-dev
sudo apt-get -y install python-pip
sudo apt-get -y install python-dev
sudo apt-get -y install python-matplotlib
sudo apt-get -y install gfortran libopenblas-dev liblapack-dev
sudo apt-get -y install libcgal-dev
sudo apt-get -y install python-numpy
sudo apt-get -y install python2.7-config
sudo apt-get -y install python-cairo
sudo apt-get -y install python-scipy
sudo apt-key adv --keyserver pgp.skewed.de --recv-key 98507F25
echo 'deb http://downloads.skewed.de/apt/trusty trusty universe' | sudo tee -a /etc/apt/sources.list
echo 'deb-src http://downloads.skewed.de/apt/trusty trusty universe' | sudo tee -a /etc/apt/sources.list
sudo apt-get update
sudo apt-get -y --force-yes install python-graph-tool