Yes, it is definitely correct. Repetition of now can be used to show different aspects at different points in time:
now (something), now (something else)
At one time or in one instance being one way, and then at another time being a completely different way.
- The manager keeps changing his outlook on the project, now really hopeful, now very pessimistic. (FreeDict)
I see that not all dictionaries record this use of repetitive now. AHD does:
At times; sometimes: now hot, now cold.
So in your sentence this structure is used to mean that the representation of Agamemnon points to different aspects of his figure at different points. From the larger context it may become clearer whether this is meant to underline the thoroughness of this representation or the complexity of the character.