Multiple data in scatter matrix

from pandas.tools.plotting import scatter_matrix
import pandas as pd
from sklearn import datasets

iris = datasets.load_iris()
iris_data = pd.DataFrame(data=iris['data'],columns=iris['feature_names'])
iris_data["target"] = iris['target']

color_wheel = {1: "#0392cf", 
               2: "#7bc043", 
               3: "#ee4035"}
colors = iris_data["target"].map(lambda x: color_wheel.get(x + 1))
ax = scatter_matrix(iris_data, color=colors, alpha=0.6, figsize=(15, 15), diagonal='hist')