In this paper, we introduce a service-based NOMA scheme for industrial environments with a high density of end devices using multiple wireless services simultaneously. With three main services defined in 5G, there is a need for a flexible and low-latency transmission scheme. OMA schemes are inefficient in resource allocation, making NOMA one of the key candidates for efficient resource allocation. Additionally, NOMA is known for serving multiple end devices with a limited amount of resources simultaneously. We present an algorithm for generating an equidistant signal constellation diagram, which is suitable for service-based NOMA as it does not require careful power allocation like user-based NOMA. Furthermore, we compare the performance of our approach to an OMA system.