Use a stock vector illustration and recolor in Adobe Illustrator it to make it unique to your brand.
1. Open your vector file in Illustrator.
2. Select the image (or elements of the image) that you want to recolor.
3. Select in the Menu bar Edit / Edit Colors / Recolor Artwork...
4. In the color wheel, change the color by using your mouse to move the color handles around/up and down the wheel.
For more control over the recoloring, you can hit the "Advanced Options..." button and manually change each color that appears in the illustration.