Short answer: dress like a shravaka if you are a shravaka. The key is modesty and cleanliness, not a special ceremonial dress for swadhyaya.

What to keep in mind

• For lay followers (shrāvakas): wear clean, simple, modest clothes. The idea is to keep distractions away and stay focused on study and reflection.
• For monks/monastic vows: Digambar monks traditionally practice nudity (as part of their renunciation), while Shwetambar monks wear simple white robes. Those are different paths and not applicable to a layperson performing swadhyaya.
• Swadhyaya itself is about studying Jain scriptures, contemplating right conduct, and deepening spiritual understanding. The clothes you wear should support concentration and inner purification, not become a ritual centerpiece.
• Practical tips: sit in a clean place, maintain personal hygiene, cover the head if your tradition prescribes it, and avoid flashy or costly attire during study times to keep the mind steady.

If you’d like, I can share more on modest dress norms for shravakas in your specific tradition (Digambar or Shwetambar) or suggest a simple swadhyaya routine.