Similar to name a contact category, you can change the contact category color in Outlook. If you do not like the contact category colors, you can change them with the steps below:
Step 1: Click "People" button to open the contact window;
Step 2: Click the "Categorize" button from the "Home" tab;
Step 3: Choose "All Categories" from the drop-down list;
Step 4: In the "Color Categories" window, click the category you want to change the color and click the "Color" box;
Step 5: Choose a color from the drop-down colors and click "OK" to finish.