Algorithm for generating a map, or how to build a map from "objects"?

Question

Java

Good day!
At first I wanted to paint everything, but then I realized that so most likely I would only get confused myself and confuse you.
That's why I decided to immediately show my "bike" and diagrams, so that I can ask questions based on them.
And so the way is when I build a map with my hands, first I draw it on paper, then I draw it from objects in code.

Location l1 = new Location();
l1.setName("l1");
Location l2 = new Location();
l2.setName("l2");
Location l3 = new Location();
l3.setName("l3");
Location l4 = new Location();
l4.setName("l4");
Location l5 = new Location();
l5.setName("l5");
Location l6 = new Location();
l6.setName("l6");
Location l7 = new Location();
l7.setName("l7");
Location l8 = new Location();
l8.setName("l8");
Location l9 = new Location();
l9.setName("l9");
Location l10 = new Location();
l10.setName("l10");
Location l11 = new Location();
l11.setName("l11");
Location l12 = new Location();
l12.setName("l12");
Location l13 = new Location();
l13.setName("l13");
Location l14 = new Location();
l14.setName("l14");
Location l15 = new Location();
l15.setName("l15");
Location l16 = new Location();
l16.setName("l16");
Location l17 = new Location();
l17.setName("l17");
Location l18 = new Location();
l18.setName("l18");
Location l19 = new Location();
l19.setName("l19");
Location l20 = new Location();
l20.setName("l20");

l1.setDown(l2);
l2.setUp(l1);
l2.setLeft(l6);
l6.setRight(l2);
l6.setDown(l7);
l7.setUp(l6);
l7.setDown(l8);
l8.setUp(l7);
l8.setDown(l9);
l9.setUp(l8);
l9.setDown(l19);
l19.setUp(l9);
l19.setRight(l18);
l18.setLeft(l19);
l18.setRight(l17);
l17.setLeft(l18);
l17.setRight(l16);
l16.setLeft(l17);
l16.setRight(l14);
l14.setLeft(l16);
l14.setDown(l15);
l14.setUp(l13);
l15.setUp(l14);
l13.setDown(l14);
l13.setUp(l12);
l12.setDown(l13);
l12.setLeft(l11);
l11.setRight(l12);
l11.setLeft(l10);
l10.setRight(l11);
l10.setUp(l5);
l5.setDown(l10);
l5.setUp(l3);
l3.setDown(l5);
l3.setRight(l4);
l4.setLeft(l3);
l3.setLeft(l2);
l2.setRight(l3);
l8.setRight(l20);
l10.setLeft(l20);
l20.setRight(l10);

Those. the result is such a map

. Of course, in this way, you can probably make a beautiful and cool map.
But it's not buzz.
So, does anyone have any ideas how to achieve the same result, but with the help of an algorithm?
To avoid misunderstanding.

l1.setDown(l2); //Говорим что из локации L1 мы можем пройти в локацию L2
l2.setUp(l1); // Соответственно и из локации L2 мы можем вернуться в локацию L1
...
и так далее.

Well, accordingly, such teleports should not work