Answer: like a linear equation where the slope is the constant value of the acceleration.
Step-by-step explanation:
As you know, acceleration is the rate of change of the velocity over time, so if we integrate the acceleration over the time, we obtain the equation for the velocity (plus a constant, which is the initial velocity)
If we have a constant acceleration;
a(t) = c
we integrate it and get:
v(t) = c*t + constant.
This is a linear equation, so the graph where the acceleration is constant, looks like a linear equation with slope equal to the constant.