A cover letter complements your resume to showcase your personal brand. Start with a concise introduction, clubbing in your goal to join the company. Focus on the core skills you bring to the table.
Bring in the elements of your current role with a short description of your KRA. Then add 3-5 top achievements you have had over the last decade, which will help the executive recruiter see the actual value and remove the fluff.

You should complete the cover letter with a call to action statement to streamline communication.