Digitization, connected networks, embedded software, and smart devices have resulted in a major paradigm shift in business models. Transformative service-based business models are dominating the market, where advancement in technology has paved the way for offering not only a set of new services but also altering product functionalities and services over time. This paradigm shift calls for new design approaches. Designers should be able to design flexible products and services that can adapt to a wide range of consumer needs over time. To address the need for designing for flexibility, the objective of this study is to develop a graph coloring technique that can model changes in the functional requirements of a product and determine the minimum number of physical parts needed to meet future functionalities. This technique relies on vertex labeling by the designer and the construction of a core graph combining key elements of all desired iterations, which is then colored by label. One numerical example and one real-world example are provided to show the application of the proposed model.