Suggest a way to get specific email objects based on specific events

I have a Event hierarchy with some types of it namely WelcomeEvent, LogOffEvent, BilledEvent etc. I want to generate different kind of emails for these events. What I do is have a abstract Email class with types WelcomeEmail, LogoffEmail, BilledEmail. I have a EmailFactory inside which I have following method:

Email getEmail(Event event) {
    if(event.instanceOf(WelcomeEvent))
        return new WelcomeEmail(event);
    if(event.instanceOf(LogOffEvent))
        return new LogoffEmail(event);
    if(event.instanceOf(LogOffEvent))
        return new BilledEmail(event);

}

My reviewer says that instanceOf should be avoided as much as possible.

Is there a better way of doing this?