How can i visualiize the peeks over the graph?

My code for R peeks extraction:

   m1=max(ca2)*.40;%to test
          P=find(ca2>=m1);
          y_levels=ca2(P);

          P_loc=[];
          diff_pp=[];
          for k=1:length(P)-1
              diff=abs(P(k) - P(k+1));
              if(diff>20)
                  P_loc=[P_loc P(k)];
                  diff_pp=[diff_pp diff];
              end
          end
          diff_pp_min=min(diff_pp);
          diff_pp_max=max(diff_pp);
          diff_pp_mean=mean(diff_pp);

          diff_pp_amp=max(y_levels);

ca2 being the coefficient after the wavelet decomposition

ca2=appcoef(c,l,'db4',2);

any feedback regarding how i can improve it and visualize the peeks on my EGC signal