As per the workflow, 'hold on' should let the peak points be drawn on the same axis. For a simple example, try running the following in the MATLAB Command Window:
data = [25 8 15 5 6 10 10 3 1 20 7];
ax1=subplot(2,1,1);
plot(ax1,data)
hold on;
findpeaks(data)
This lets the original plot and the peaks to be in the same axis.
Also, as the 'findpeaks' function can return the location of the peak points, you can also plot the peaks as per the following manner:
data = [25 8 15 5 6 10 10 3 1 20 7];
ax1=subplot(2,1,1);
plot(ax1,data)
hold on;
[pks,locs] = findpeaks(data);
plot(ax1,locs,pks,'go')
