From http://stackoverflow.com/questions/1838873/visualizing-branch-topology-in-git

.gitconfig

[alias]
    lg = !"git lg1"
    lg1 = !"git lg1-specific --all"
    lg2 = !"git lg2-specific --all"
    lg3 = !"git lg3-specific --all"

    lg1-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold green)(%ar)%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)'
    lg2-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset)%C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset) %C(dim white)- %an%C(reset)'
    lg3-specific = log --graph --abbrev-commit --decorate --format=format:'%C(bold blue)%h%C(reset) - %C(bold cyan)%aD%C(reset) %C(bold green)(%ar)%C(reset) %C(bold cyan)(committed: %cD)%C(reset) %C(bold yellow)%d%C(reset)%n''          %C(white)%s%C(reset)%n''          %C(dim white)- %an <%ae> %C(reset) %C(dim white)(committer: %cn <%ce>)%C(reset)'