In Warhammer 40,000, the Tau Empire is typically associated with a specific color scheme, which includes a combination of blue, white, and black. The primary color of the Tau army is blue, which is used on the majority of their units and vehicles. The blue color is typically a light, almost sky-blue color, which is meant to represent the Tau's advanced technology and their emphasis on unity and cooperation. White is also a common color in the Tau army, and it is often used as an accent color on various parts of the model. This color is often used to represent the clean and sterile environment of the Tau's advanced technology. Black is also frequently used in the Tau army, and it is often used as a secondary color on various parts of the model. This color is often used to represent the sleek and stealthy nature of the Tau's technology. Some Tau army have a different approach, like the Vior'la Sept Cadre, who use a red and white color scheme. This color scheme is used to represent the Vior'la Sept Cadre's specialties in stealth, infiltration and speed. It's worth noting that different Sept or region of the Tau empire might have different color schemes, and the players are free to customize their army as they like, as long as it's coherent and easy to distinguish on the battlefield.