@VinayVaidya111 Ji has explained well. In addition, this may also be noted. अञ्जू व्यक्ति-म्रक्षण-कान्ति-गतिषु is the root. (Here, व्यक्ति = making known, म्रक्षण = wetting/sprinkling with some liquid such as Ghee etc., कान्ति = brightness/illumine and गति = to go/move). From this, in the meaning of नितराम् (नि - उपसर्ग) अनक्ति (the root अञ्जू) इति (नि+अञ्ज्), the noun is derived as न्यङ्गः or न्यङ्गम्, Meaning part, mark, akin etc. Then we fix it in a compound as श्वेतः च अङ्गः च = श्वेताङ्गः meaning “white mark” or “white spot” or “white part” etc. Or we can have alternative compound बहुव्रीहिः as श्वेतं/तः न्यङ्गं/न्यङ्गः यस्य सः = श्वेतन्यङ्गः meaning one who has white mark/spot/part.
Though श्वेतन्यङ्गः can be said to denote any God (Vishnu/Brahma/Shiva etc.) by etymology, it is not found as name of Vishnu or Shiva anywhere in Sanskrit literature. However, For Brahma, it is seen.
In शतपथब्राह्मण (४-५-१०(२)), it is used to mean akin in "एष वै सोमस्य न्यङ्गो यदरुणपुष्पाणि फाल्गुनानि" meaning this (they) – the brown flowers of Phalguna plant are akin to Soma plant.