What I did was this:
1. Create a vector line for the curve with the Pen tool. Set the tool to Path mode.
2. Select your foreground color for the first line, change your Paint brush settings so it has a very small radius/size.
3. From the Paths panel, click the Stroke button. This will use the Paint brush tool settings to trace a line along the path.
4. Use the Path Selection tool to move the path to the next position, select the next color, increase the Brush size. Stroke.
5. Repeat for each line.
For the bottom section (with the brown/yellow), use the Magic Wand or Quick Select tool to select the bottom blank area. Then use the Gradient tool (with your foreground and background colors set to the yellow and brown respectively). Set the Gradient tool to Foreground/Background gradient and use a Radial gradient. Then trace out your first gradient. Set the blend mode to Lighten and do the second circle.
Here is the example I made (just a quick 5 minute affair, so excuse the crudeness):