I agree with Dipil. I realize that it can be very uncomfortable and unsettling when restrooms are not used appropriately. In most instances, we "react" with anger and contempt towards the person causing the mess.
But take a moment to think that perhaps this fresher hasn't been exposed to the hygiene standards prevalent in your company. I know this might sound really stupid at first, but believe me, a large proportion of us Indians are not used to "toilet and bathroom etiquette" until we start work, especially if we don't come from large or relatively large cities. Why? There are a number of reasons. Some of these would be cultural, domestic, socio-economic, lack of adequate infrastructure while growing up, etc.
In any case, as flustered as you guys probably are at work, try cutting her some slack. Speak with her and educate her. Don't instruct her. Remember, even you wouldn't like someone telling you that you don't know how to use a toilet. After all, it's something you've been doing from the moment you were born. So, it becomes very personal and can be extremely sensitive.
I am sure that with patience, tact, empathy, and a desire to educate, she will learn new skills, and you guys will get the restroom that you rightly deserve!
Cheers!