What is the difference between the title of Sales Representative and Sales Executive?

I think they're pretty much interchangeable. Actually, the most 'current' term would be 'Account Executive"

Rep is the regular worker who answers to a supervisor or manager and the executive is the person who answers directly to the CEO as the head of the entire sales division.

Sales representative is not outdated. It is still widely used. And the difference is basic and simple: Sales representative: is a person employed to represent a business and to sell its merchandise or services, as to customers in a store or customers who are visited. The primary function of professional sales is to generate and to close leads, educate prospects, fill needs and satisfy wants of consumers appropriately, and therefore turn potential customers into actual paying customers. A sales executive has a role more geared towards the administration part of sales and has the function of carrying out of plans or orders. Basically, the sales executive is usually the immediate supervisor of the sales representative. Sorry... your boss wins...