Problem with DKIM for Domain Alias

We created the website using a temporary domain name as the master domain: colorpage.printsafe.net

We have made the website public using a Domain alias: colorpage.store

When I check the DKIM settings, I see dkim keys for the temporary domain name:

However, I see no way to create a DKIM record for the Domain alias is used on the live website and will be used for outgoing email.