1) Use a fine-mesh sieve to prepare segments to a large platter. Save any juice.
2) Slice oranges, and lime crosswise into 1/4" thick rounds and layer atop grapefruit segments and some orange segments.
3) In small bowl, combine 1/2 reserved juice with maple syrup Pour syrup mixture over citrus.
4) (Citrus can be stored, covered, in a refrigerator for up to 1 day.)
5) Sprinkle coconut over citru and gently toss.
6) Garnish with tarragon before serving.