Requirements analysis for generating a conceptual model such as an Entity Relationship Diagram (ERD) is an essential task in software development life cycle. In this paper, we are presenting a Natural Language Processing (NLP) based approach to generate the ERD from requirements in an unrestricted format such as general requirements, user stories or Use Case Specification (UCS). To assess the performance and correctness of the proposed technique, we compare our approach with existing automated techniques by processing the same requirements. The preliminary results show a significant improvement.