A great way for a company to communicate everything it does to improve security, is to create and maintain a security page (usually /security) and whitepaper. You don't want to divulge too much information there, but definitely enough so that a potential customer or partner can have confidence that you are paying attention to security.
The whitepaper can be as simple as a PDF of the /security webpage. You can take it a step further and add graphics to the page. It's an excellent tool for sales people to send to potential customers.
The mere fact of having a security page and whitepaper puts you well ahead of the rest.
Below are some examples of security whitepapers from reputable companies. They are often part of a security page on a website and include a combination of infographic style communication.