Unless you want to go bright and Caribbean, I suggest soft greens and blues -- with a neutral background, if you prefer -- for a restful feeling your guests will surely appreciate. You could add some items in a deeper version of the colour you choose (first pic below).

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Do you already have furniture and linens for the room or do you plan to furnish after you paint? That said, blues and greens are always nice for bedrooms like rina suggests.

Usually a color scheme for a bedroom comes from the bedding so maybe that would be a good start. I like gray bedrooms for a bit of drama or as mentioned soft blues and greens