为什么使用networkx库制作的图形显得凌乱？

Question

def printtree(root,temp):
    global countleaf
    spaces = temp.level * 10
    if temp.leaf:
        print(" " *(spaces) + "=>If it is ", end=" ")
        print(temp.when)
        print(" "*spaces,end=" "),
        print("Did he/she will play:"+str(temp.ans)+"  Level("+str(temp.level)+")")
        return
    if root!=temp:
        print(" " * spaces+"=>If it is ",end=" ")
        print(temp.when)
    print(" "*spaces,end=" ")
    print("Class:"+str(temp.question)+"   Level("+str(temp.level)+")")
    for i in range(len(temp.children)):
        if temp.children[i].question!=None:
            G.add_edges_from([(str(temp.question),str(temp.children[i].question))],label=str(temp.children[i].when))
        else:
            countleaf = countleaf + 1
            G.add_edges_from([(str(temp.question), str(temp.children[i].ans+"("+str(countleaf)+")"))], label=str(temp.children[i].when))
        printtree(root,temp.children[i])






pos=nx.spring_layout(G)
edge_labels=dict([((u,v,),d['label'])
                 for u,v,d in G.edges(data=True)])
nx.draw_networkx_nodes(G,pos,cmap=None,node_size=2500)
nx.draw_networkx_labels(G, pos)
nx.draw_networkx_edge_labels(G,pos,edge_labels=edge_labels)
nx.draw_networkx_edges(G,pos,arrows=True,arrowsize=70,width=6,style='dashed',alpha=0.5)
plt.show()

制作决策树图（可视化）。每次我运行程序图时，外观都会有所不同。

如何更改代码，使图形看起来像决策树？

我正在根据这些数据制作决策树：

|----------+------+----------+-------+------|
| Outlook  | Temp | Humidity | Windy | Play |
| Rainy    | Hot  | High     | FALSE | No   |
| Rainy    | Hot  | High     | TRUE  | No   |
| Overcast | Hot  | High     | FALSE | Yes  |
| Sunny    | Mild | High     | FALSE | Yes  |
| Sunny    | Cool | Normal   | FALSE | Yes  |
| Sunny    | Cool | Normal   | TRUE  | No   |
| Overcast | Cool | Normal   | TRUE  | Yes  |
| Rainy    | Mild | High     | FALSE | No   |
| Rainy    | Cool | Normal   | FALSE | Yes  |
| Sunny    | Mild | Normal   | FALSE | Yes  |
| Rainy    | Mild | Normal   | TRUE  | Yes  |
| Overcast | Mild | High     | TRUE  | Yes  |
| Overcast | Hot  | Normal   | FALSE | Yes  |
| Sunny    | Mild | High     | TRUE  | No   |
|----------+------+----------+-------+------|

以下是该图的示例：