。
She's just as attractive as her older sister.
Literal
She [topic-は] older-sister [comparison-と] same-way [as-に] attractive is.
~と同様に is the standard equal-comparison frame. と marks the standard of comparison; 同様 ('same manner') links them; に turns it adverbial. The polite copula です sits at the end. The ~的 suffix attaches to 魅力 ('charm, allure') to form the productive な-adjective 魅力的 ('attractive, charming') — ~的 is a hugely productive nominal-to-adjectival deriver in Japanese. Slightly more polished and formal than the everyday ~と同じくらい frame.