The personification of Gayatri Mantra is as old as the mantra itself. The mantra was given the form of a female deity. Here is the symbolic meaning of Gayatri Dhayana Mantra.
A Dhyana Mantra
I worship Gayatri with five faces of different colors – pearl, coral, gold, blue and white. Each faces have three eyes, a gem-studded crown with a crescent moon on it. Her essence consists in all the tattvas and the syllable. Gayatri has ten hands held in Vara and Abhya Mudras with goad, whip, water pot, white skull, rope, conch, wheel and lotus flower in the hands.
Symbolically the five faces here stand for the five sense organs and five pranas. The three eyes stand for the three Gunas (Sattva, Rajas and Tamas). It also represents Bhur Bhuvah or Svah. The three eyes also stand for vigilance, dream and deep sleep.
Three Gayatri Dhayana expounded in the Ishanashivagurudevapaddhati
One must meditate on Gayatri, mounted on a swan, in a white lotus, decorated with red jewels, having eight eyes and four faces, carrying a string of crystals, a sruva, a pot, a stick in her four hands. She is the mother of the three worlds, the adorable morning dawn, in the disc of the sun as its deity and the source of Vedic hymns.
Savitri (Gayatri) should be meditated with a yellow garment shines adorable in the disc of the sun at noon; mounted on a Garuda, with lotus like eyes shining black like the indranila gem. She carries conch, wheel, club and lotus flower in her four hands. She is the support of the whole world. She keeps reciting the Yajur Veda. Shining with the luster of many strings of pearls tossing around her, this is the Vaishnava form of Gayatri.
One must meditate on Savitri having five faces and three eyes, having the crescent moon on the head, and with shining matted hair of yellow. Her ornaments are snakes and their “manis” (diamonds) which shine like a lighting. Two of her hands carry Khavanga (cot-leg like weapon) and spear. Two of her hands are in abhaya (fearlessness) and varada posture (boon giving). She has a garment made out of fully-grown tiger skin. She sings the Sama Veda. This Gayatri form is associated with Shaivism.