Electric power systems are complex structures with a continuously varying status of the system. Because of this, they require fast and innovative online monitoring methods to observe the evolving status of the system. Within the power system, online monitoring of the generators coherency and transmission adequacy represent some of the biggest challenges. Furthermore, to assist the Transmission System Operators (TSOs), a functionality for the ease of understanding and visualization of such phenomena must be included in the solution. This paper proposes a novel online measurement-based representation method for visualizing the coherent generation groups within a power system by mapping the simulation/data time-series into particles motion. The mapping also allows a reduction of the space-temporal dimension to a coordinate system that permits the visualization of other properties of the generators' signals such as the direction, linking-distance, overlapping, and the notion of inertia by their rapid movement. Additionally, a modified version of a clustering method specialized on particles - the so-called Friends of Friends (FoF) algorithm - is applied. This algorithm allows computation of the aforementioned properties and rapidly identifies the formed coherent groups. The method is applied to the well-known IEEE 9-bus test system for verifying the coherent groups reflected in the time-shots. Results show that the proposed visualization method is suitable for rapidly tracking the coherency features.