Methods, apparatus, systems, and computer-readable media are provided for tailoring composite graphical assistant interfaces for interacting with multiple different connected devices. The composite graphical assistant interfaces can be generated proactively and/or in response to a user providing a request for an automated assistant to cause a connected device to perform a particular function. In response to the automated assistant receiving the request, the automated assistant can identify other connected devices, and other functions capable of being performed by the other connected devices. The other functions can then be mapped to various graphical control elements in order to provide a composite graphical assistant interface from which the user can interact with different connected devices. Each graphical control element can be arranged to reflect how each connected device is operating simultaneous to the presentation of the composite graphical assistant interface.