Her original design is to resemble a female figure despite her being bloody huge, the story for which this is made places her in a huge malfunctioning body. It is not until later on that she switches to a portable module which she can move freely detached from the AI bodycasing.
The initiation for the build of this body was started in 1986, considering technology back then a whole lot was not possible, mostly how to place all of the operating system into a small body. Its just old bulky and damaged.
Her being designed to 'integrate with humanity' is not entirely the true disposition of her role. She is build to supervise testing and not to chitchat with them, If she had to move things around in the facility it merely seemed more convenient to have her big until she has the needed equipment to get it done for her.