Food is just part of the story with a cat's affections. Although some people say cats "don't feel love", this is not particularly true, and they can bond deeply with people who are kind to them. If you and your mother have spent time with the cat, shared your affection with her by petting, grooming, talking and playing with her, or allowed her to rub against your legs or sleep on or near you, you've formed a bond that goes beyond being a mere source of food, and she considers you part of her family.
Most cats will bond with people who they share lots of positive social interactions with, so if your maids are around a lot and play or cuddle with the cat, she might start to share her love with them as well. If your cat has negative interactions with the maids, even accidental ones (like for example, if they don't notice she is asleep in the room and turn on the vacuum, scaring her), she will probably continue to be more distant with them.
There is also some truth to the idea that cats just love who they love, and may choose a favorite person in the family with no obvious reason, even if everyone in the household equally feeds and pets them. Anecdotally, some breeds are more likely to be 'one person cats' than others, and this mainly comes down to personality of the cat.