How do I update Nvidia display driver on ubuntu 18.04, if I already installed cuda toolkit 10.2 and its bundled display driver?

I installed CUDA toolkit 10.2 on ubuntu 18.04 LTS. I previously did not have any nvidia display drivers, so it came bundled with the 418 version display driver. This seemed to work fine.

I noticed on the NVIDIA site that the latest driver was 430. I want to update my display driver from 418 to 430. How can I do this?

[Downloading the driver directly] (https://www.nvidia.com/Download/index.aspx), and then running the installer, doesn’t work; it gives a complaint that Nvidia is already running with Xorg.