How do I graph to see the similarity matrix for summarizing with TextRank algorithm

Question

I am using the TextRan algorithm for inferential text summarization.I used Glove model for word embedding. I wrote a code that can draw a graph to display how a similarity matrix.Although I get the same summary text every time I run the code, I see a different graph drawing each time. What is the reason of this? Is this a problem or is it normal? If it is a problem, how can I provide a solution? If you have information, I would appreciate it if you reply.

def GloveİleSentenceEmbed(sentence_list,sentence_stem):
  word_embeddings = {} 
  f = open('/content/drive/MyDrive/MetinAnalizi/glove.6B.100d.txt', encoding='utf-8')
  for line in f:
    values = line.split()
    word = values[0]
    coefs = np.asarray(values[1:], dtype='float32')
    word_embeddings[word] = coefs
  f.close()
  sentence_vectors = []  
  for i in sentence_stem:
    if len(i) != 0:
      v = sum([word_embeddings.get(w, np.zeros((100,))) for w in i])/(len(i)+0.001)
    else:   
      v = np.zeros((100,))
    sentence_vectors.append(v)
  return sentence_vectors

def SimilariytMatrix(sentence_list,sentence_vectors):
  similarity_matrix=np.zeros([len(sentence_list), len(sentence_list)])
  for i in range(len(sentence_list)):
    for j in range(len(sentence_list)):
      if (i!=j):
         similarity_matrix[i][j] = cosine_similarity(sentence_vectors[i].reshape(1,100), sentence_vectors[j].reshape(1,100))[0,0]
  similarity_matrix = np.round(similarity_matrix,3)
  return similarity_matrix

def PageRankAlgorithm(similarity_matrix,sentence_list):
    nx_graph = nx.from_numpy_array(similarity_matrix)
    plt.figure(figsize=(10, 10))
    pos = nx.spring_layout(nx_graph)
    nx.draw(nx_graph, with_labels=True, font_weight='bold')
    plt.show()