An executive summary that sits on top of a management consulting document is usually a page that summarises the recommendations, next steps, and decisions. It is meant for an insider, the executive reading it is likely to have a 90% understanding of what is inside the document. There is no need for graphics here, a few dry bullets with decisions will do the trick to remind everyone of what will happen next, and who will do it.
So, this is totally the opposite of the other use of an executive summary that I come across often: a short teaser to someone who has no understanding at all of what you want to achieve. Here, a dense text, or a dry list of bullets will do the opposite of attracting attention.
Feel free to step away from the habit of sending dense text pages to get people excited about your project. Instead, think of the time you want the recipient to spend on your document. Now, fill that time with the most visually pleasing and exciting way to present your case. Lower your expectations, you do not want to close a deal at this stage, you want a phone call, or a next meeting. Sending a short, visual presentation that can stand on its own without verbal explanation is a perfect reply to the request for an executive summary.