Printing diagram numbers for Feynman diagrams

Question

I have the following code to print Feynman diagrams generated by some program. file is

\documentclass[11pt]{article}
\usepackage{graphicx} % Allows for eps images
\usepackage{multicol} % Allows for multiple columns
\usepackage[compat=1.1.0]{tikz-feynman}
\usepackage[textsize=tiny,backgroundcolor=white]{todonotes}
\usepackage[top=1in, bottom=1.25in, left=0.8in, right=0.8in]{geometry}

\begin{document}
%\maketitle
\centering
{\LARGE\bf{Generating Feynman diagrams}
\centering
\date{today}
}
\begin{center}
    \feynmandiagram[small]{%diagram_number_1
4 -- [ anti fermion,color=violet ] 1,
 1 -- [ anti fermion,color=violet ] 5,
 4 -- [ gluon,color=green ] 2,
 6 -- [ anti fermion,color=violet ] 2,
 5 -- [ gluon,color=green ] 3,
 3 -- [ anti fermion,color=violet ] 7,
 7 -- [ anti fermion,color=violet ] 4,
 5 -- [ anti fermion,color=violet ] 6,
 7 -- [ boson,color=blue ] 6,
 ext1 [particle=] -- [boson,color=blue] 1,
ext2 [particle=] -- [fermion,color=red] 2,
ext4 [particle=] -- [anti fermion,color=violet] 3,
};
\feynmandiagram[small]{%diagram_number_2
4 -- [ anti fermion,color=violet ] 1,
 1 -- [ anti fermion,color=violet ] 5,
 4 -- [ gluon,color=green ] 2,
 6 -- [ anti fermion,color=violet ] 2,
 5 -- [ gluon,color=green ] 3,
 3 -- [ anti fermion,color=violet ] 7,
 7 -- [ anti fermion,color=violet ] 4,
 5 -- [ anti fermion,color=violet ] 6,
 7 -- [ boson,color=blue ] 6,
 ext1 [particle=] -- [boson,color=blue] 1,
ext2 [particle=] -- [fermion,color=red] 2,
ext4 [particle=] -- [anti fermion,color=violet] 3,
};
\end{center}
\end{document}

when run by lualatex, the auto alignment produces the following pdf

Now, I want to give name at the bottom of each diagrams, without changing the alignment (first fillup horizontal and then go to the next line), but with diagram number printed at the bottom. My initial try was using figure environment, but it places every diagrams one by one vertically. Help is required.