How to Edit/Save color sequence in design?

Go to Colors>> Edit Color Sequence…

You will get a window as shown below:

You can simply drag the colors in the sequence required and also can choose from the sorting option to sort colors according to the available options.

Also you can choose the sorting order

And then click OK.

This will create a new layer on top of your design and preserves its color sequence. Now, even if you edit your design, the color sequence will remain intact.