This is basically just a sequencing game where the subject matter lends itself to a vertical, rather than a horizontal, diagram. This is unusual, but not unheard of. On past exams, for instance, there has been a game with a layer cake, where some flavors are above or below other flavors. Or another with an apartment building, where certain people live above or below other people.
You basically have two main options – draw a normal sequencing game diagram, framed by the numbers 1-6, but rotated 90 degrees, so instead of 1 being on the left and 6 on the right, 1 will be on the bottom, and 6 on top. Then symbolize your rules accordingly – for instance, the white-green block will be vertical, rather than horizontal.
If that’s too weird, you can do a typical sequencing diagram, with 1 on the left and 6 on the right. If you do this, you’ll want to add a written reminder of the orientation, for instance:
1 (lowest). 2. 3. 4. 5. 6 (highest)
Then your White-Green block would be a normal horizontal block.
There’s no right or wrong here; it’s just whatever makes most sense to you. My personal preference, though, and my recommendation to students, is Option 1. I think it’s least confusing when the diagram matches the subject material as much as possible. Then words like “higher,” “lower,” “above,” or “below” in the question stems retain their natural, intuitive meaning, and that tends to reduce confusion, especially when you’re working quickly.