Map domains so permalinks show domain not subdomain


I would like to clarify something if I may.

I have a multisite setup with subdomains.
These have been mapped to the clients purchased domains and all is working well.

I noticed that my permalinks all show as the subdomain, for example:

Am I able to change this so it reads:

Or does it even matter? I want to make sure that the sites and content are optimised for SEO purposes.

Thanks in advance.

Richard C