She was portrayed several times during her life by Bronzino. The changes that occurred between 1550 and 1560 are stunning.
Her Wikipedia article is here.

1543 Eleonora di Garzia di Toledo (1553–1576) wife of Don Pietro de' Medici by Agnolo Bronzino (Národní galerie v Praze - Praha Czech Republic)

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy)

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy) reticulated partlet

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy) fabric and jeweled girdle

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy)

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy) slashed sleeve roll

1544 through 1545 Eleonora di Toledo col figlio Giovanni (Galleria degli Uffizi - Firenze, Toscana Italy) sleeve

1549 Eleonora of Toledo and her son Francesco by Agnolo Bronzino (Museo Nazionale di Palazzo Reale - Pisa, Toscana, Italy)

Eleanora of Toledo with a View of Florence behind after Agnolo Bronzino (Ashmolean Museum, University of Oxford - Oxford, Oxfordhire, UK)

1550-1555 Noblewoman, possibly Eleonora de Toledo, by Angelo Bronzino (Galleria Sabauda - Torino, Piemone Italy)

1560 Eleonora de Toledo by Agnolo Bronzino (Staatliche Museen zu Berlin, Gemäldegalerie - Berlin Germany)

1571 -1576 (between) Eleonora (Dianora) of Toledo (Medici) by a worker in the Alessandro Allori studio (State Hermitage Museum - St. Petersburg Russia)

1572 Eleonora di Toledo by Allesandro Allori (Palazzo Vecchio (Palazzo della Signoria) - Firenze, Toscana Italy)

1572 SAS la duchessa di Toscana Eleonora d'Álvarez di Toledo e Osorio Pimentel by Allesandro Allori (Palazzo Vecchio (Palazzo della Signoria) - Firenze, Toscana Italy)
