Graph will be the same and it will be in the first quadrant only.
For both the cases (ie For y=mx and y=mx+c)
If x,y, positive -> First quadrant
If x positive and y negative -> 4th quadrant
If x negative and y positive -> 2nd Quadrant
If x and y negative -> 3rd quadrant
Sign of m doesnt matter when quadrant is considered. But if m is negative then the curve will be downwards opposite to as given