You can use all HTML (or HTML and a span class) to color specific internal links, but Obsidian doesn’t consider these “real” links. e.g. Page preview looks working, but they aren’t registered as outgoing links, backlinks, and probably don’t work as expected in other spots. e.g.
<a href="Plugins make Obsidian special for you.md" class="internal-link" style="color: salmon">link to the Plugins make Obsidian special for you note</a>
This is a <a href="Plugins make Obsidian special for you.md" class="internal-link" style="color: salmon">link to the Plugins make Obsidian special for you note</a> and this is a <a href="start here.md# What is this place?" class="internal-link" style="color: blue; background-color: orange">link to the Start here note > what is this place </a> heading.
I personally wouldn’t use these unless it was absolutely necessary, and sparingly.