Answer:
Depends on the specific relation of acceleration as function of time, but it would always look like decresing or increasing negatively.
Step-by-step explanation:
Acceleration is the derivative of velocity with respect to time. That means that it is the change. The fact that is negative means that it is decreasing, or increasing in the negative direction (i.e. going backwards faster).
Attached is the graph with constant negative acceleration, using kinematics relations, it would be a linear equation with negative slope.