Diagrammed rhymes with:
monogrammed, monogrammed, programmed, reprogrammed, monogrammed, programmed, reprogrammed, monogrammed, programmed, reprogrammed
Diagrammed sounds like:
degrand, dejarnett, dejarnette, dichromate, disagreement, disarmament, disarmed, discerned, discernment, discriminate, discriminated, disorient, disoriented