Hi,
I found a solution. Kindly look into that, hope it helps.
Reference - https://sourav-566913.outsystemscloud.com/DataGridSample/Home.aspx?_ts=637379668149877981
Click on the "Change Cell Color" link on the page and it will change the color of cell "Part No."
Add one custom css class in your page -

I added one link in the page "Change Cell Color". Onclick event I called a javascript to change the cell color.
This is the function I added in the page javascript. Then I am calling the function to the link OnClick. Here I am passing the cellindex.


Check and let me know if it is your requirement.
Thanks
Sourav